JP6034813B2 - Rotation angle measuring device - Google Patents

Description

  The present invention relates to a rotation angle measuring device using a magnetic focusing plate.

In recent years, various uses of a highly functional magnetic sensor LSI in which a magnetic detection element (Hall element, magnetoresistive element, etc.) and a signal processing circuit (LSI) are integrated have been advanced. For example, in an automobile, there is a rotation angle sensor for detecting the rotation angle of a handle. This type of rotation angle sensor is proposed in Patent Document 1, for example. This Patent Document 1 discloses a rotation angle sensor using a magnetic converging plate that collects and amplifies a surrounding magnetic field and a Hall element on a silicon substrate.
FIG. 1 is a configuration diagram for explaining a rotation angle sensor described in Patent Document 1. In FIG. The rotation angle sensor includes a rotating magnet 1 attached to a rotating body, and an integrated circuit (silicon substrate) 2 placed under the rotating magnet 1. The silicon substrate 2 has the silicon substrate 2 disposed on the silicon substrate 2. 2 and a magnetic flux concentrating plate 4 is provided on the Hall element 3. The rotation angle of the rotary magnet 1 is calculated by detecting a magnetic field (transverse magnetic field) parallel to the plane of the silicon substrate 2 generated from the rotary magnet 1 using the magnetic converging plate 4 and the Hall element 3. is there.

  FIG. 2 is a view for explaining the arrangement of the Hall elements and the magnetic focusing plates formed on the silicon substrate in FIG. With the plane parallel to the silicon substrate 2 as the XY plane, a circular magnetic focusing plate 4 is arranged around the origin on the XY plane, and four Hall elements 3 are arranged below the circumference of the edge of the magnetic focusing plate 4. ing. The Hall elements (H0, H180) 3 are arranged on the X axis at a symmetrical position with the origin as the center, and the Hall elements (H90, H270) 3 are similarly arranged on the Y axis at the symmetrical position with respect to the origin. Yes. H0 and H90 are arranged at positions having positive coordinate components in the XY coordinate plane of FIG.

FIG. 3 is a cross-sectional view of the rotating magnet, the magnetic focusing plate, the Hall element, and the silicon substrate in FIG. 1 as viewed along the X-axis direction. A direction perpendicular to the rotating magnet 1 from the silicon substrate 2 is the Z-axis positive direction, and a direction from H180 to H0 is the X-axis positive direction. Two Hall elements are drawn below the edge of the magnetic focusing plate 4 at positions symmetrical to the center of the magnetic focusing plate 4. The magnetic sensitive surfaces of these Hall elements H0 and H180 are perpendicular to the plane of the silicon substrate 2. Therefore, the magnetic field in the Z-axis direction is detected.
However, as shown in FIG. 3, since the magnetic field generated from the rotating magnet 1 is attracted to the magnetic convergence plate 4, the transverse magnetic field parallel to the plane of the silicon substrate 2 (X-axis component in FIG. 3) is It is bent in a direction perpendicular to the plane of the silicon substrate 2 (Z-axis direction) and passes through the magnetic sensitive surface of the Hall element. Therefore, these Hall elements can detect a transverse magnetic field as a signal.

With such a configuration, the Hall elements H0 and H180 shown in FIG. 2 detect the X-axis component and the Z-axis component of the magnetic field incident on the magnetic converging plate 4, and similarly, H90 and H270 have the Y-axis component and the Z-axis component. Detect axis component.
In FIG. 2, a state in which the magnetic field incident on the magnetic focusing plate 4 is incident counterclockwise from the X axis around the origin in the direction of θ is depicted. At this time, H0 detects the X-axis component of the magnetic field with a positive sign output (+ Vx), and H180 detects with a negative sign output (-Vx). Similarly, H90 detects the Y-axis component of the magnetic field with a positive sign output (+ Vy), and H270 detects with a negative sign output (-Vy). All the four Hall elements detect the Z-axis component of the magnetic field as the positive sign output (+ Vz) in the direction of incidence on the XY plane.

Therefore, the signals HVX and HVY detected by the difference between H0 and H180 and the difference between H90 and H270 are
HVX = + Vx + Vz − (− Vx + Vz) = 2Vx (1)
HVY = + Vy + Vz − (− Vy + Vz) = 2Vy (2)
It becomes. That is, the X-axis component and the Y-axis component of the magnetic field strength. The Z-axis component is canceled and not detected.
Here, the rotation angle sensor calculates the magnetic field angle θ from HVX and HVY θ = atan (HVY / HVX) (3)
As follows. Note that the angle can be calculated in this way because the magnetic field strength under the magnetic converging plate with respect to the rotating magnetic field shows an ideal sinusoidal change.

FIG. 4 is a block configuration diagram for explaining the signal processing of the rotation angle sensor according to Patent Document 1 described above. The rotation angle sensor includes Hall elements H0, H180, H90, and H270, an X-axis subtraction unit 11X that subtracts detection signals of H0 and H180, a Y-axis subtraction unit 11Y that subtracts detection signals of H90 and H270, and an X-axis The calculation unit 12 calculates an angle from the output of the subtraction unit 11X (expression (1)) and the output of the Y-axis subtraction unit 11Y (expression (2)) according to the expression (3).
In addition, the angle calculation method described in Patent Document 2 does not use the XY coordinate system as described above, and a plurality of Hall elements arranged at equal intervals below the circumference of the magnetic converging plate perform signal output. The angle is calculated from the outputs of two adjacent Hall elements having different signs.

In such a rotation angle sensor, the offset of the Hall element, the calculated angle generated when the offset and gain of the amplifier that amplifies the signal from the Hall element are different between the X axis and the Y axis, and the rotating magnetic field to be detected The angle error is a problem, and several solutions have been proposed. For example, Patent Document 3 reduces the offset of the Hall elements by arranging the Hall elements of the magnetic flux concentrating plate so as to have a mirror image relationship. Further, for example, Patent Document 4 reduces the angle error by performing coordinate conversion on the X component signal and the Y component signal detected by the magnetic sensors arranged on the X axis and the Y axis.
Further, for example, Patent Document 5 discloses a method for reducing an angle error generated due to a magnetic field distortion of an external magnet. The rotation angle sensor described in Patent Document 5 reduces errors caused by MR (magnetoresistive) elements or errors caused by distortion of the magnetic field of an external magnet.
Furthermore, for example, Patent Document 6 discloses a method of calculating each axis component by using two or more Hall elements using a magnetic focusing plate.

US 2002/0021124 (A1) US Pat. No. 7,235,968 (B2) JP 2012-150003 A JP 2010-190872 A JP 2011-158488 A Japanese Patent Laid-Open No. 2004-25795

In the rotation angle measuring device using the magnetic converging plate and the Hall element targeted by the present invention, attention must be paid to the properties of the magnetic converging plate.
The magnetic converging plate is linearly magnetized with respect to the applied magnetic field in a weak magnetic field, but is no longer linearly magnetized when a magnetic field having a certain intensity or more is applied. For the sake of convenience, such a point that is not magnetized linearly is defined as a magnetic saturation point, and a phenomenon that is not linearly magnetized is defined as magnetic saturation (phenomenon).
FIG. 5 shows how the magnetic field intensity changes below the circumference of the magnetic convergence plate at an angle of 0 to 360 degrees formed from the application direction when a magnetic field of 50 mT and 100 mT is applied to the magnetic convergence plate with a magnetic saturation point of 70 mT. FIG. In FIG. 5, the magnetic field intensity in the 0 degree direction (parallel to the applied magnetic field) is normalized to 1. As can be seen from FIG. 5, when a magnetic field of 50 mT below the magnetic saturation point is applied, the magnetic field intensity below the magnetic focusing plate forms an ideal sine wave (cosine wave) with respect to the angle of the magnetic field (diamonds in FIG. 5). It can be seen that the plot and the line connecting them) become a distorted sine wave when a magnetic field of 100 mT above the magnetic saturation point is applied (the square plot in FIG. 5 and the line connecting them).
Therefore, when the magnetic field above the magnetic saturation point is rotated, the change in the magnetic field is not an ideal sine wave, and an error occurs in the calculated angle of the rotation angle measuring device described above.

FIG. 6 is a diagram simulating an angle error included in the angle calculated by the rotation angle sensor when a rotating magnetic field of 100 mT above the magnetic saturation point described above is applied.
As can be seen from FIG. 6, the angle error is 0 degree, 45 degree, 90 degree, and every 45 degrees, the minimum (near 0 degree). , Called a quadruple wave of the angle error). This angular error is caused by magnetic saturation of the magnetic focusing plate. It is important to detect that such magnetic saturation has occurred in a highly accurate and highly reliable rotation angle measuring device. The occurrence of magnetic saturation is equivalent to, for example, that the magnet attached to the rotating shaft is displaced from the original position or the rotating shaft is displaced, which is an undesirable failure for the user of the rotation angle measuring device. . Also, an increase in angular error is undesirable from the point of control. For example, in the case of a rotation angle measuring device for motor control use, the angle error leads to torque ripple.

However, none of Patent Documents 1 to 6 discloses a method for detecting this magnetic saturation.
Particularly recently, in the field of automobiles such as power steering systems, functional safety conforming to ISO 26262 has been required. In order to comply with ISO26262, the inventors have found that a rotation angle measuring device used in the field of automobiles must be able to detect a failure of a rotating magnet or the like at high speed. That is, the inventors have found a new problem that magnetic saturation must be detected quickly and reliably when magnetic saturation of the magnetic focusing plate occurs due to, for example, a rotating magnet failure.
The present invention has been made in view of such problems, and an object of the present invention is to prevent a control system including a rotation angle measuring device using a rotating magnet from malfunctioning due to a failure of the rotating magnet or the like. Therefore, an object of the present invention is to provide a rotation angle measuring device that can detect magnetic saturation quickly and reliably in a rotation angle measuring device using a magnetic converging plate.

The present invention has been made in order to achieve such an object, and is a rotation angle measuring device including a plurality of Hall element pairs, and a magnetic field provided on a magnetic sensitive surface of the plurality of Hall element pairs. a converging plate, the magnetic flux concentrator, based on the a rotating magnet disposed proximate to the magnetic flux concentrator, the output signals of the plurality of pairs of pre-Symbol plurality of Hall elements pairs to cover in a plan view, of the rotating magnet One or more angle calculation units for calculating a plurality of rotation angle information; an amplitude calculation unit for calculating a plurality of amplitude information based on the plurality of pairs of output signals respectively corresponding to the plurality of rotation angle information; and the plurality of rotations Failure of the rotation angle measurement device based on angle information and a comparison result between the difference between two pieces of amplitude information among the plurality of amplitude information and the first reference signal output from the first reference signal output unit A failure detection unit for detecting A rotation angle measuring device.
The rotation angle measuring device includes a plurality of Hall element pairs, the magnetic convergence plate provided on the magnetic sensitive surface of the plurality of Hall element pairs, and the magnetic convergence plate so as to cover the magnetic convergence plate in plan view. a rotary magnet which is arranged close to the magnetic flux concentrator, and the previous SL more based on the output signals of a plurality of pairs of Hall element pairs, the one or more angle calculation section that calculates a plurality of rotation angle information of the rotating magnet, wherein An amplitude calculator that calculates a plurality of amplitude information based on the plurality of pairs of output signals respectively corresponding to a plurality of rotation angle information, the plurality of rotation angle information, and a first amplitude among the plurality of amplitude information The comparison result between the information and the first reference signal output from the first reference signal output unit, the second amplitude information different from the first amplitude information among the plurality of amplitude information, and the second reference signal output The result of comparison with the second reference signal Zui and a rotational angle measuring device comprises a a failure detection unit for detecting a failure of the rotation angle measurement device.
The rotation angle measuring device includes a plurality of Hall element pairs, the magnetic convergence plate provided on the magnetic sensitive surface of the plurality of Hall element pairs, and the magnetic convergence plate so as to cover the magnetic convergence plate in plan view. An amplitude calculator that calculates a plurality of amplitude information representing the magnetic field intensity from the rotating magnet, based on output signals of a plurality of pairs of the plurality of Hall element pairs, and a rotating magnet disposed in proximity to the magnetic focusing plate; Comparing a difference between two pieces of amplitude information among a plurality of pieces of amplitude information and a first reference signal output from the first reference signal output unit, and detecting a failure in the rotation angle measuring device; The rotation angle measuring device is provided.
The rotation angle measuring device includes a plurality of Hall element pairs, the magnetic convergence plate provided on the magnetic sensitive surface of the plurality of Hall element pairs, and the magnetic convergence plate so as to cover the magnetic convergence plate in plan view. An amplitude calculator that calculates a plurality of amplitude information representing the magnetic field intensity from the rotating magnet, based on output signals of a plurality of pairs of the plurality of Hall element pairs, and a rotating magnet disposed in proximity to the magnetic focusing plate; Of the plurality of amplitude information, the first amplitude information is compared with the first reference signal output from the first reference signal output unit, and the second amplitude different from the first amplitude information among the plurality of amplitude information. A rotation angle measurement device comprising: a failure detection unit that compares amplitude information with a second reference signal output from a second reference signal output unit and detects a failure of the rotation angle measurement device.

Further, the failure detection unit, characterized in that further said plurality of rotation angle information, on the basis of the third reference signal the reference signal output section of the 3 outputs, to detect a failure of the rotation angle measurement device And
Further, the failure detection unit detects a failure of the rotation angle measurement device based on two differences among the plurality of rotation angle information and the third reference signal.
In addition, a difference calculation unit that calculates the difference is provided.
Further, the failure detection unit detects magnetic saturation of the magnetic flux concentrating plate .

Also, the failure detection unit, based on the plurality of rotational angle information, and outputs the first failure determination signal indicating whether the or the rotational angle measuring device is faulty, based on said plurality of amplitude information , Outputting a second failure determination signal indicating whether or not the rotation angle measuring device is in failure, and when at least one of the first and second failure determination signals indicates failure, the rotation It is characterized in that it is determined that the angle measuring device is out of order.

The failure detection unit outputs a first failure determination signal indicating whether or not the rotation angle measurement device is in failure based on the plurality of rotation angle information, and based on the plurality of amplitude information, A second failure determination signal indicating whether or not the rotation angle measuring device is out of order is output, and one rotation angle information among the plurality of rotation angle information and two rotation angles among the plurality of rotation angle information. Determination of magnetic saturation of the magnetic convergence plate based on information difference, difference between two pieces of amplitude information among the plurality of amplitude information, the first failure determination signal, and the second failure determination signal And determining a failure of the plurality of Hall element pairs.

The failure detection unit outputs a first failure determination signal indicating whether or not the rotation angle measurement device is in failure based on the output of the angle calculation unit, and based on the first amplitude information. And outputting a second failure determination signal indicating whether or not the rotation angle measuring device is out of order, and indicating whether or not the rotation angle measuring device is out of order based on the second amplitude information. A failure determination signal is output, and when at least one of the first to third failure determination signals indicates a failure, the rotation angle measuring device is determined to be defective.
In addition, the plurality of pairs are at least three pairs, and the failure detection unit calculates two or more differences between two pieces of rotation angle information among the plurality of pieces of rotation angle information, A failure of the rotation angle measuring device is detected based on the third reference signal.

The failure detection unit compares the two or more differences with the third reference signal and outputs a signal indicating whether or not the rotation angle measurement device is in failure, and among these signals, When at least one of them indicates a failure, the rotation angle measuring device is determined to be a failure .

Also, the failure detection unit, based on the first amplitude information, and outputs the first failure determination signal indicating whether the or the rotational angle measuring device is faulty, based on the second amplitude information Output a second failure determination signal indicating whether or not the rotation angle measuring device is in failure, and when at least one of the first to second failure determination signals indicates failure, It is characterized by determining that the rotation angle measuring device is out of order.

Further, the plurality of Hall element pairs are arranged so as to be shifted by 45 degrees below the circumference around the origin of the polar coordinates when the polar coordinates are defined on the magnetic convergence plate. And
The plurality of Hall element pairs have an angle that is an integer multiple of 90 ° / N (N is an integer of 2 or more) with respect to the origin of the polar coordinates when the polar coordinates are defined on the magnetic convergence plate. Two Hall element pairs are arranged across the coordinate axes of the above.

  According to the present invention, in order to prevent a control system including a rotation angle measuring device using a rotating magnet from malfunctioning due to a failure of the rotating magnet or the like, in the rotation angle measuring device using a magnetic convergence plate, magnetic saturation is performed. Provided is a rotation angle measuring device capable of detecting quickly and reliably. This effect according to the present invention is very useful particularly in a rotation angle sensor used in a safety demanding application such as for in-vehicle use.

It is a block diagram for demonstrating the rotation angle sensor of patent document 1. FIG. It is a figure for demonstrating arrangement | positioning of the Hall element formed on the silicon substrate in FIG. 1, and a magnetic convergence board. It is sectional drawing which looked at the rotating magnet in FIG. 1, a magnetic concentrating board, a Hall element, and the silicon substrate along the X-axis direction. It is a block block diagram for demonstrating the signal processing of the rotation angle sensor by patent document 1. FIG. It is a figure which shows the mode of a change of the magnetic field intensity under the magnetic converging plate circumference in the angle of 0 degree-360 degree | times made from an application direction, when the magnetic field of 50mT and 100mT is applied to the magnetic converging plate of 70 mT of magnetic saturation points. It is the figure which simulated the angle error contained in the angle which a rotation angle measuring device calculates, when a 100 mT rotating magnetic field more than a magnetic saturation point is applied. It is a figure explaining arrangement | positioning of the Hall element of Embodiment 1 of the rotation angle measuring device which concerns on this invention. The figure which simulated angle error (DELTA) (theta) and (DELTA) (theta) 45 contained in the angle which a rotation angle measuring device calculates, when a 100 mT rotating magnetic field 70 mT or more of magnetic saturation points is applied to the magnetic convergence plate of the rotation angle measuring device shown by FIG. It is. It is a figure which shows the simulation result of (theta) d when a 100 mT rotating magnetic field more than the magnetic saturation point 70mT is applied to the magnetic convergence board of the rotation angle measuring apparatus shown by FIG. It is a block diagram which shows the signal processing circuit of Embodiment 1 of the rotation angle measuring device which concerns on this invention. It is a figure which shows the specific example of the rotation angle information correction | amendment part shown to FIG. 10A, and has shown the case where a rotation angle information correction | amendment part is an average value calculation part. It is a figure which shows the specific example of the rotation angle information correction part shown to FIG. 10A, and has shown the case where a rotation angle information correction part is an addition value calculation part. It is a figure which shows the specific example of the rotation angle information correction | amendment part shown to FIG. 10A, and has shown the case where a rotation angle information correction | amendment part is a median value calculation part. When θa = 30 °, a simulation of angle errors Δθ, Δθt, Δθave included in the angles calculated by the rotation angle measurement device when a rotating magnetic field of 100 mT above the magnetic saturation point is applied to the magnetic focusing plate It is. It is a figure which shows the simulation result of (theta) d when a 100 mT rotating magnetic field more than a magnetic saturation point is applied to a magnetic converging plate when it is set to (theta) a = 30 degree. It is a figure explaining arrangement | positioning of the Hall element of Embodiment 2 of the rotation angle measuring device which concerns on this invention. It is the figure which simulated angle error (DELTA) (theta), (DELTA) (theta) 30, (DELTA) (theta) 60 which generate | occur | produces by a magnetic saturation, when a 100 mT rotating magnetic field 70 mT or more of magnetic saturation points is applied to the magnetic convergence board of the rotation angle measuring apparatus shown by FIG. It is a figure which shows the simulation result of (theta) d and (theta) d 'when a 100 mT rotating magnetic field 70 mT or more of magnetic saturation points is applied to the magnetic convergence board of the rotation angle measuring apparatus shown by FIG. It is a block diagram which shows the signal processing circuit of Embodiment 2 of the rotation angle measuring device which concerns on this invention. It is a figure which shows the example of a change of Embodiment 1 shown in FIG. It is a block diagram which shows the signal processing circuit of Embodiment 3 of the rotation angle measuring device which concerns on this invention. It is a circuit block diagram which shows the specific example of the failure detection part in FIG. The amplitude value M (solid line) calculated from the output of the Hall element in the arrangement A and the amplitude value calculated from the output of the Hall element in the arrangement B before the magnetic saturation with respect to the magnetic convergence plate of the rotation angle measuring device shown in FIG. It is a figure showing how Mc (dotted line), amplitude value M (one-dot chain line), and amplitude value Mc (two-dot chain line) after magnetic saturation change with rotation of an input magnetic field. It is a figure which shows the simulation result of (theta) d and Md when a rotating magnetic field more than a magnetic saturation point is applied with respect to the magnetic convergence board of the rotation angle measuring apparatus shown by FIG. It is a circuit block diagram which shows the other specific example of the failure detection part in FIG. It is a circuit block diagram which shows the other specific example of the failure detection part in FIG. The angle error Δθ, θd, and Md of the first rotation angle θ when the magnetic focusing plate is magnetically saturated and when the output of the Hall element H0 in the XY coordinate system is short-circuited (output is 0). It is a figure showing the simulation result of. It is a block diagram which shows the signal processing circuit of Embodiment 4 of the rotation angle measuring device which concerns on this invention. It is a block diagram which shows the signal processing circuit of Embodiment 5 of the rotation angle measuring device which concerns on this invention.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In each embodiment, a rotation angle information correction unit or an average value calculation unit is provided, but it may not be used when not required.
First, the first embodiment will be described using two coordinate systems, and the second embodiment will be described using three coordinate systems.
[Embodiment 1]
FIG. 7 is a diagram for explaining the arrangement of the Hall elements of the first embodiment of the rotation angle measuring device according to the present invention. A plurality of Hall elements H0, H45, H90, H135, H180, H225, H270, and H315 are arranged every 45 degrees counterclockwise below the circumference of the circular magnetic convergence plate 14. Of the plurality of Hall elements H0, H45, H90, H135, H180, H225, H270, and H315, H0 and H180 are one Hall element pair, H45 and H225 are one Hall element pair, and H90 and H270 are one Hall element. The pair H135 and H315 form one Hall element pair. A circular magnetic convergence plate 14 is provided on the magnetic sensitive surfaces of the plurality of Hall element pairs. A rotating magnet is disposed close to the magnetic converging plate 14 so as to cover the magnetic converging plate 14 in plan view.

The center point G of the circular magnetic convergence plate 14 is also the midpoint of the line segment connecting the plurality of Hall element pairs H0 and H180, H45 and H225, H90 and H270, and H135 and H315. When the X axis is formed on the straight line from H180 to H0 and the Y axis is formed on the straight line from H270 to H90, the same XY coordinate system as in the conventional case of FIG. 2 can be formed. On the other hand, when the straight line from H225 to H45 is formed on the X45 axis and the Y45 axis is formed on the straight line from H315 to H135, the XY coordinate system is obtained by rotating the XY coordinate system 45 degrees counterclockwise about the G center.
In other words, the plurality of Hall element pairs are respectively arranged at the positions of the coordinate axes of the coordinate system that is an integral multiple of 90 ° / N. In this case, N = 2, and the plurality of Hall element pairs are respectively arranged at the coordinate axis positions of the coordinate system of 0 times and 1 times of 90 ° / N. Moreover, it is preferable that the plurality of Hall element pairs are shifted by 45 degrees below the circumference of the magnetic flux concentrating plate.

As in the prior art, the difference between H0 and H180 is an output signal (HVX and HVY, respectively) representing the X component of the magnetic field and the difference between H90 and H270 is the Y component of the magnetic field. Similarly, the difference between H45 and H225 is an output signal (HVX45 and HVY45, respectively) representing the X45 component of the magnetic field, and the difference between H135 and H315 is the Y45 component of the magnetic field.
Here, the arrangement of the Hall elements H0, H90, H180, and H270 constituting the XY coordinate system is referred to as arrangement A, and the arrangement of the Hall elements H45, H135, H225, and H315 constituting the XY45 coordinate system is referred to as arrangement B. .

If the magnetic field B incident on the magnetic converging plate is incident in the direction of θ counterclockwise from the X axis with the origin as the center, assuming that the signal amplitude representing the magnetic field strength is V _B HVX = V _B cos θ
HVY = V _B sin θ
It becomes. On the other hand, if the magnetic field B is similarly incident in the direction of θ45 counterclockwise from the X45 axis,
HVX45 = V _B cos θ45
HVY45 = V _B sin θ45
It becomes. The angles θ and θ45 are expressed by the following equations, respectively.
θ = atan (HVY / HVX)
θ45 = atan (HVY45 / HVX45)
Here, the cases where there is no angular error are defined as θideal and θ45ideal, respectively.

Since the XY45 coordinate system is obtained by rotating the XY coordinate system 45 degrees counterclockwise, assuming that the angle obtained by adding 45 ° to θ45 is θc, it is the same as θideal when there is no angle error. That means
θc = θ45 + 45 °
θc_ideal = θ45 ideal + 45 ° = θ ideal
Assuming that due to magnetic saturation, Δθ is generated in the XY coordinate system and Δθ45 is generated in the XY45 coordinate system, θ = θideal + Δθ respectively.
θ45 = θ45 ideal + Δθ45
It becomes. And
θc = θ45 + 45 ° = θ45 ideal + Δθ45 + 45 ° = θideal + Δθ45
Thus, the angle error of θc is Δθ45.

FIG. 8 shows angular errors Δθ and Δθ45 included in the angles calculated by the rotation angle measurement device when a 100 mT rotation magnetic field with a magnetic saturation point of 70 mT or more is applied to the magnetic convergence plate of the rotation angle measurement device shown in FIG. It is the figure which simulated.
The angle calculation error Δθ by the Hall element in the arrangement A with respect to the magnetic field angle is represented by a solid line in the figure, and is the same fourth harmonic as in FIG. On the other hand, the angle error Δθ45 of θc obtained by adding 45 ° to the angle calculation θ45 by the Hall element of the arrangement B forming the XY45 coordinate system is represented by a dotted line in the figure and is the same fourth harmonic as Δθ. The polarity is reversed. This is because Δθ45 measured in the XY45 coordinate system is out of phase by 4 × 45 ° = 180 ° with respect to Δθ. Table 1 shows the polarities for each angle range of Δθ and Δθ45.

It can be seen that the angle error has the opposite polarity in any angular range. Therefore,
Δθ + Δθ45 ≒ 0
It becomes. That is, in the present invention, the XY45 coordinate system is arranged to generate an angular error that cancels the angular error generated in the XY coordinate system.
Here, θave is the average value of θ and θc,
θave = (θ + θc) / 2 = (θideal + Δθ + θideal + Δθ45) / 2≈θideal
Thus, even if an angle error occurs due to magnetic saturation, the angle of the XY coordinate system can be obtained with high accuracy. That is, by calculating the angle in the XY coordinate system, calculating the angle in the XY45 coordinate system, and correcting the rotation angle information of the rotating magnet from the plurality of rotation angle information θ and θc (arithmetic average in the above example), It realizes highly accurate magnetic field angle measurement. A one-dot chain line in FIG. 8 is a residual error Δθave of θave, which is clearly reduced as compared with Δθ and Δθ45.

Next, the quick and reliable detection of magnetic saturation, which is an effect of this embodiment, will be described.
If magnetic saturation is not occurring,
Δθ−Δθ45 = 0
Obviously. However, when magnetic saturation occurs, the polarities of Δθ and Δθ45 are as shown in Table 1 except for the vicinity of the angle of K × 45 ° (K is an integer from 0 to 7) at which the fourth harmonic of the angle error becomes 0 °. Is different,
It is also clear from the above description that Δθ−Δθ45 ≠ 0. Therefore, when θ and θc are calculated, the difference θd is
θd = θ−θc = Δθ−Δθ45 ≠ 0
It is. If an appropriate threshold θd_lim is determined,
| Θd | <θd_lim
According to the relational expression (| θd | is the absolute value of θd), if | θd | is larger than θd_lim, magnetic saturation can be detected. That is, magnetic saturation that cannot be detected only by the calculated angle θ of the XY coordinate system can be detected by using the calculated angle θ45 of the XY45 coordinate system.

FIG. 9 is a diagram illustrating a simulation result of θd when a rotating magnetic field of 100 mT having a magnetic saturation point of 70 mT or more is applied to the magnetic focusing plate of the rotation angle measuring device shown in FIG. It can be seen that θd is not 0 except for an angle of K × 45 °, at which no angle error due to saturation originally occurs due to magnetic saturation.
FIG. 10A is a configuration diagram illustrating a signal processing circuit of the first embodiment of the rotation angle measurement device according to the present invention. 10A includes a first Hall element pair 21 (H0, H180) and a second Hall element pair 22 (H90, H270) in arrangement A, and a third Hall element pair 23 in arrangement B ( H45, H225), the fourth Hall element pair 24 (H135, H315), MUX (multiplexer) 25, X-axis subtractor 26X, Y-axis subtractor 26Y, angle calculator 27, first Storage register 28 a, second storage register 28 b, rotation angle information correction unit 29, and failure detection unit 30. The failure detection unit 30 includes a subtraction unit 31, a threshold comparison unit 33, and a threshold memory 32.

  That is, the rotation angle measuring apparatus according to the first embodiment includes a plurality of Hall elements H0 to H315 provided on the substrate, and a magnetic converging plate 14 provided on the magnetic sensitive surfaces of the plurality of Hall elements H0 to H315. And a rotation angle measuring device that measures a rotation angle of a rotating magnet disposed in the vicinity of the magnetic flux converging plate 14 so as to cover the magnetic flux converging plate 14 in plan view. The rotation angle measuring apparatus according to the first embodiment includes a plurality of Hall element pairs configured by a plurality of Hall elements H0 to H315, and a first Hall element pair 21 that detects a magnetic component in a first direction. (H0, H180), the second Hall element pair 22 (H90, H270) for detecting the magnetic component in the second direction different from the first direction, and the first direction and the second direction A third Hall element pair 23 (H45, H225) that detects a magnetic component in a third direction in a different direction and a magnetic component in a fourth direction that is different from the first direction to the third direction are detected. And a fourth Hall element pair 24 (H135, H315).

  Based on the output signal strengths of the first Hall element pair 21 and the second Hall element pair 22 that are one pair of the plurality of Hall element pairs, the angle calculation unit 27 performs the first rotation angle of the rotating magnet. θ is calculated. Then, the angle calculation unit 27 generates the second rotating magnet second based on the output signal strengths of the third Hall element pair 23 and the fourth Hall element pair 24 which are one pair of the plurality of Hall element pairs. The rotation angle θc is calculated. That is, the angle calculation unit includes a plurality of pairs of Hall element pairs (first Hall element pair 21 and second Hall element pair 22, third Hall element pair 23, and fourth Hall element pair 24). A plurality of pieces of rotation angle information of the rotating magnet are calculated based on the output signal intensity. That is, the plurality of pairs include one set (one pair) constituted by the first Hall element pair 21 and the second Hall element pair 22, and the third Hall element pair 23 and the fourth Hall. One pair (one pair) composed of the element pair 24, and a pair composed of two Hall element pairs among the plurality of Hall element pairs respectively corresponds to a plurality of rotation angle information. Means there are multiple. Here, the intensity of the output signal is the voltage of the output signal. That is, it is a Hall electromotive force signal output by the Hall element according to the input magnetic field.

The subtraction unit (difference calculation unit) 31 calculates a difference between the first rotation angle θ and the second rotation angle θc. Further, the threshold value comparison unit 33 (also simply referred to as the comparison unit 33) detects a failure of the rotation angle measurement device from the output of the subtraction unit (difference calculation unit) 31 and the reference signal output from the threshold value memory (reference signal output unit) 32. Is detected. Here, the threshold comparison unit 33 detects magnetic saturation of the magnetic convergence plate 14.
The rotation angle information correction unit 29 corrects rotation angle information from the first rotation angle θ and the second rotation angle θc. This correction is based on information on the rotation angle having a larger error with respect to the true rotation angle of the first rotation angle θ and the second rotation angle θc, and the rotation having the smaller error with respect to the true rotation angle. This is a correction that gives angle information and outputs rotation angle information close to the true rotation angle. As a result, the dynamic range determined by the magnetic saturation of the magnetic focusing plate is widened.

10B to 10D are diagrams illustrating specific examples of the rotation angle information correction unit illustrated in FIG. 10A. FIG. 10B illustrates a case where the rotation angle information correction unit is an average value calculation unit, and FIG. 10C illustrates rotation angle information. When the correction unit is an addition value calculation unit, FIG. 10D shows a case where the rotation angle information correction unit is a median value calculation unit.
In FIG. 10B, the average value calculation unit 29 calculates the average value θave from the first rotation angle θ and the second rotation angle θc. The average value θave is an arithmetic average, but not limited to the arithmetic average, a geometric average or a harmonic average may be output.

  In FIG. 10C, the addition value calculation unit 29 outputs the addition value θadd from the first rotation angle θ and the second rotation angle θc. In this embodiment, θadd is about twice the true rotation angle, and a value close to the true rotation angle can be obtained by providing a divider, attenuator or bit shifter (not shown) in the subsequent stage. In particular, when θadd is expressed as a digital signal, the same information as the arithmetic average can be obtained by discarding the lower bits and taking out the upper bits. The user of the present rotation angle measurement device may read θadd as twice the true rotation angle, and may read that half the value of θadd is close to the true rotation angle.

In FIG. 10D, the median value calculation unit 29 outputs a median value θcenter from the first rotation angle θ and the second rotation angle θc. When there are two pieces of rotation angle information, it is the same as the arithmetic mean, but when it is three or more, it becomes a median value. In this form, for example, when one of a plurality of pieces of rotation angle information has an extreme error, that is, when it is an abnormal value (jump value), the influence of the abnormal value can be made extremely small.
Hereinafter, in all the embodiments, the rotation angle information correction unit 29 will be described as an average value calculation unit 29. The average is an arithmetic average. Needless to say, in all the embodiments, the average value calculation unit 29 may calculate a geometric average or a harmonic average, or may calculate an addition value or a median value.

10B, the output of the first Hall element pair 21 (H0, H180) in arrangement A, the output of the second Hall element pair 22 (H90 and H270), and the third Hall element pair 23 in arrangement B ( H45, H225) and the output of the fourth Hall element pair 24 (H135 and H315) are output to the MUX 25, respectively.
The MUX 25 outputs the output of the first Hall element pair 21 (H0, H180) in the arrangement A and the output of the second Hall element pair 22 (H90 and H270) at the time φ1 to the X-axis subtractor 26X and the Y-axis, respectively. It outputs to the subtraction part 26Y. The X-axis subtractor 26X and the Y-axis subtractor 26Y output output signals HVX and HVY to the angle calculator 27, respectively.

The angle calculation unit 27 calculates the angle θ of the XY coordinate system at the time φ1, and outputs it to the first storage register 28a. At time φ2, the MUX 25 outputs the outputs of the third Hall element pair 23 (H45, H225) and the fourth Hall element pair 24 (H135 and H315) of the arrangement B to the X-axis subtracting units 26X and Y, respectively. Output to the axis subtractor 26Y. X-axis subtractor 26X and Y-axis subtractor 26Y output output signals HVX45 and HVY45 to angle calculator 27, respectively.
The angle calculation unit 27 calculates the angle θ45 of the XY45 coordinate system at time φ2, and outputs the angle θc corrected by 45 ° to the second storage register 28b. The first and second storage registers 28a and 28b output θ and θc to the average value calculation unit 29 and the failure detection unit 30, respectively. The average value calculation unit 29 calculates θave from θ and θc. In θave, the angle error due to magnetic saturation is reduced.

  Θ and θc input to the failure detection unit 30 are input to the subtraction unit 31. The subtractor 31 calculates θd from θ and θc, and outputs it to the comparator (threshold comparator) 33. The comparison unit 33 determines whether magnetic saturation has occurred from θd and the threshold value θd_lim (reference signal) stored in the threshold value memory (reference signal output unit) 32. That is, the comparison unit 33 outputs “1” if magnetic saturation is detected, and “0” if it is not magnetic saturation. That is, the failure detection unit 30 detects a failure of the rotation angle measurement device based on the output of the angle calculation unit and the threshold value θd_lim of the threshold memory. The failure detection in this embodiment can detect a failure in which the rotating magnet approaches the magnetic convergence plate. In other words, the present embodiment can determine that magnetic saturation has occurred, and outputs saturation information if it is determined that magnetic saturation has occurred.

As described above, in the rotation angle measuring device using the magnetic converging plate 14, the magnetic saturation of the magnetic converging plate 14 can be detected quickly and reliably.
The XY45 coordinate system as the additional coordinate system is obtained by rotating the XY coordinates by 45 ° around G. However, the XY45 coordinate system is not limited to the 45 ° rotation, and an area in which Hall elements for the additional coordinate system can be arranged. In principle, magnetic saturation can be detected at any angle θa within the range of 0 ° to 90 ° that can ensure.
Assuming that θc = θt + θa with respect to the angle θt calculated in the additional coordinate system,
θave = (θ + θc) / 2
Then, the angle error Δθave becomes smaller than Δθ and Δθt. (Since Δθt is a waveform with different phases of Δθ, the average of both is smaller than the original waveform.)

FIG. 11 shows that when θa = 30 °, an angular error Δθ, Δθt, Δθave included in an angle calculated by the rotation angle measuring device when a rotating magnetic field of 100 mT above the magnetic saturation point is applied to the magnetic focusing plate. It is the figure which simulated. In the figure, the solid line is Δθ, the dotted line is Δθt, the alternate long and short dash line is Δθave, and it can be seen that Δθave is reduced compared to Δθ and Δθt.
On the other hand, in the case of magnetic saturation detection,
θd = θ−θc
Is θd = 0 when not magnetically saturated, and θd ≠ 0 when saturated, and magnetic saturation can be detected by the method described above.

FIG. 12 is a diagram illustrating a simulation result of θd when a rotating magnetic field of 100 mT above the magnetic saturation point is applied to the magnetic convergence plate when θa = 30 °. It can be seen that θd is not 0 due to magnetic saturation.
As described above, even when θa is not 45 °, the above-described effects can be obtained and included in the present invention. However, in the case of θa = 45 °, subtraction is performed between those in which the phase of the fourth harmonic wave of the angle error is shifted by 180 °. Therefore, the variation in θd is the largest and the detection sensitivity is increased, which is suitable for using the present invention. It is.

[Embodiment 2]
FIG. 13 is a diagram for explaining the arrangement of the Hall elements according to the second embodiment of the rotation angle measuring apparatus according to the present invention.
A total of 12 Hall elements, H0, H30, H60,..., H330, are arranged at intervals of 30 ° below the circumference of the magnetic flux concentrating plate 14. The arrangement of the first Hall element pair 121 (H0, H180), the second Hall element pair 122 (H90, H270) is arranged A ′, the third Hall element pair 123 (H30, H210), the fourth Hall element The pair 124 (H120, H300) is the arrangement B ′, the fifth Hall element pair 125 (H60, H240), and the sixth Hall element pair 126 (H150, H330) is the arrangement C ′.
In other words, the plurality of Hall element pairs are arranged by being shifted by 30 degrees below the circumference of the magnetic flux concentrating plate.

The center point G of this circular magnetic focusing plate is the first Hall element pair 121 (H0, H180), the third Hall element pair 123 (H30, H210), and the fifth Hall element pair 125 (H60, H240). This is also the midpoint of the line connecting the second Hall element pair 122 (H90, H270), the fourth Hall element pair 124 (H120, H300), and the sixth Hall element pair 126 (H150, H330).
The X axis is formed on the straight line from H180 to H0 in the arrangement A ′, the Y axis is formed on the straight line from H270 to H90, and the X30 axis is similarly formed on the straight line from H210 to H30 in the arrangement B ′, and H300 to H120. The Y30 axis is formed on the straight line going to H60, the X60 axis is formed on the straight line going from H240 to H60 in the arrangement C ′, and the Y60 axis is formed on the straight line going from H330 to H150. That is, a coordinate system formed by the Hall elements of the arrangement A ′, the arrangement B ′, and the arrangement C ′ is an XY coordinate system, an XY30 coordinate system, and an XY60 coordinate system, respectively. The XY30 coordinate system and the XY60 coordinate system are coordinate systems obtained by rotating the XY coordinate system around the center point G by 30 ° and 60 °, respectively.

In other words, the plurality of Hall element pairs are respectively arranged at the positions of the coordinate axes of the coordinate system that is an integral multiple of 90 ° / N. In this case, N = 3, and the plurality of Hall element pairs are arranged at positions of the coordinate system of 0 times, 1 time, and 2 times 90 ° / N. That is, when a plurality of Hall element pairs have polar coordinates defined on the magnetic converging plate, the coordinate axes having an angle that is an integer multiple of 90 ° / N (N is an integer of 2 or more) with respect to the origin of the polar coordinates. It is arranged at each position.
The angles calculated in the respective coordinate systems are θ, θ30, and θ60, and the angle errors caused by magnetic saturation are Δθ, Δθ30, and Δθ60, respectively. When there is no angle error in the calculated angle, θ, θ30, and θ60 are expressed as θideal, θ30ideal, and θ60ideal, respectively.

FIG. 14 is a diagram simulating angle errors Δθ, Δθ30, and Δθ60 generated by magnetic saturation when a rotating magnetic field of 100 mT of a magnetic saturation point of 70 mT or more is applied to the magnetic convergence plate of the rotation angle measuring device shown in FIG. It is.
In FIG. 14, the solid line is Δθ, the dotted line is Δθ30, and the two-dot chain line is Δθ60. It can be seen that Δθ30 is 120 ° and Δθ60 is 240 ° out of phase with respect to the waveform showing the error of Δθ. This is because Δθ measured in the XY coordinate system is a quadruple wave, so Δθ30 measured in the XY30 coordinate system rotated by 30 ° and 60 ° is different in phase by 30 ° × 4 minutes, and similarly in the XY60 coordinate system. This is because the measured Δθ60 is different in phase by 60 ° × 4 minutes. Therefore,
Δθ + Δθ30 + Δθ60≈0
It becomes the relationship.
θ = θideal + Δθ
θ30 = θ30 ideal + Δθ30 = θideal-30 ° + Δθ30
θ60 = θ60 ideal + Δθ60 = θideal−60 ° + Δθ60
Therefore, here, the average value θave of θ, θ30 + 30 ° (≡θc), θ60 + 60 ° (≡θc ′) is
θave = (θ + θc + θc ′) / 3 = θideal + (Δθ + Δθ30 + Δθ60) / 3≈θideal
Thus, even if an angle error occurs due to magnetic saturation, the angle of the XY coordinate system can be obtained with high accuracy. That is, by calculating the angle in the XY coordinate system and calculating the angle also in the XY30 and XY60 coordinate systems, highly accurate magnetic field angle measurement is realized. The one-dot chain line in FIG. 14 is the residual error Δθave of θave, which is clearly reduced as compared with Δθ, Δθ30, and Δθ60.

Next, the quick and reliable detection of magnetic saturation, which is an effect of this embodiment, will be described.
When magnetic saturation does not occur as in the first embodiment,
Δθ−Δ30 = 0, Δθ30−Δ60 = 0
And when magnetic saturation occurs, except for the angles where the angle error is equal,
Δθ−Δ30 ≠ 0, Δθ30−Δ60 ≠ 0
It is. If an appropriate threshold θd_lim is determined, θd = θ−θc, θd ′ = θc−θc ′,
| Θd | <θd_lim
| Θd '| <θd_lim
Thus, the magnetic saturation of the magnetic focusing plate 14 can be detected.

  FIG. 15 is a diagram illustrating simulation results of θd and θd ′ when a rotating magnetic field of 100 mT having a magnetic saturation point of 70 mT or more is applied to the magnetic focusing plate of the rotation angle measuring device shown in FIG. In the figure, the solid line is θd, and the dotted line is θd ′. It can be seen that either θd or θd ′ is not always 0 with respect to the angle of the rotating magnetic field. By using three coordinate systems in this way, magnetic saturation can be detected more reliably than in the case of two coordinate systems.

FIG. 16 is a configuration diagram illustrating a signal processing circuit according to the second embodiment of the rotation angle measurement apparatus according to the present invention. The rotation angle measuring device of FIG. 16 includes Hall elements 121 to 126 in the group of arrangement A ′, arrangement B ′, and arrangement C ′, MUX 225, X-axis subtracting unit 226X, Y-axis subtracting unit 226Y, and angle calculating unit. 227, a first storage register 228a, a second storage register 228b, a third storage register 228c, an average calculation unit 229, and a failure detection unit 230. The failure detection unit 230 includes a first subtraction unit 231a, a first threshold comparison unit 233a, a second subtraction unit 231b, a second threshold comparison unit 233b, a threshold memory 232, and a logical sum unit 234. It is composed of
That is, the rotation angle measuring apparatus according to the second embodiment includes a plurality of Hall elements H0 to H330 provided on the substrate, and a magnetic convergence plate 14 provided on the magnetic sensitive surfaces of the plurality of Hall elements H0 to H330. And a rotation angle measuring device that measures a rotation angle of a rotating magnet disposed in the vicinity of the magnetic flux converging plate 14 so as to cover the magnetic flux converging plate 14 in plan view.

  The rotation angle measuring apparatus according to the second embodiment includes a plurality of Hall element pairs including a plurality of Hall elements H0 to H330, and detects a magnetic component in the first direction 121. (H0, H180), the second Hall element pair 122 (H90, H270) for detecting the magnetic component in the second direction different from the first direction, and the first direction and the second direction A third Hall element pair 123 (H30, H210) for detecting a magnetic component in a third direction in a different direction and a magnetic component in a fourth direction different from the first direction to the third direction are detected. And a fifth Hall element pair 125 (H60, H240) for detecting a magnetic component in a fifth direction different from the first direction to the fourth direction. ) And the first direction to the fifth direction And a sixth pair of Hall effect devices 126 for detecting the sixth direction of the magnetic component in different directions (H150, H330).

  The angle calculation unit 227 calculates the first rotation angle θ of the rotating magnet based on the output signal strengths of the first Hall element pair 121 and the second Hall element pair 122, and the third Hall element pair 123 and The second rotation angle θc of the rotating magnet is calculated based on the output signal strength of the fourth Hall element pair 124, and further, based on the output signal strengths of the fifth Hall element pair 125 and the sixth Hall element pair 126. Thus, the third rotation angle θc ′ of the rotating magnet is calculated. In other words, the angle calculation unit 227 includes a plurality of pairs of Hall element pairs (a first Hall element pair 121 and a second Hall element pair 122, a third Hall element pair 123 and a fourth Hall element pair 124, Based on the output signal intensity of the fifth Hall element pair 125 and the sixth Hall element pair 126), a plurality of rotation angle information of the rotating magnet is calculated. That is, the plurality of pairs are one set (one pair) composed of the first Hall element pair 121 and the second Hall element pair 122, the third Hall element pair 123 and the fourth Hall element. One pair (one pair) composed of the pair 124, and one pair (one pair) composed of the fifth Hall element pair 125 and the sixth Hall element pair 126, It means that there are a plurality (three sets here) of pairs composed of two Hall element pairs corresponding to a plurality of pieces of rotation angle information (here, three pieces of rotation angle information). To do. Here, the output signal strength is the voltage of the output signal. That is, it is a Hall electromotive force signal output by the Hall element according to the input magnetic field.

In addition, the failure detection unit 230 includes a first subtraction unit (difference calculation unit) 231a that calculates the difference between the first rotation angle θ and the second rotation angle θc, the second rotation angle θc, and the third rotation angle θc. A second subtracting unit (difference calculating unit) 231b that calculates a difference from the rotation angle θc ′.
In addition, a first threshold value comparison unit 233a that detects a failure of the rotation angle measurement device from the output of the first subtraction unit (difference calculation unit) 231a and the reference signal output from the threshold value memory (reference signal output unit) 232; A second threshold value comparison unit 233b that detects a failure of the rotation angle measurement device from the output of the second subtraction unit (difference calculation unit) 231b and the reference signal output from the threshold value memory (reference signal output unit) 232 I have.

The first threshold value comparison unit 233a and the second threshold value comparison unit 233b detect magnetic saturation of the magnetic flux converging plate 14. Further, an average value calculation unit 229 that calculates an average value θave from the first rotation angle θ, the second rotation angle θc, and the third rotation angle θc ′ is provided.
In FIG. 16, the output of the first Hall element pair 121 (H0, H180) in arrangement A ′, the output of the second Hall element pair 122 (H90 and H270), and the third Hall element pair in arrangement B ′. 123 (H30, H210), the output of the fourth Hall element pair 124 (H120 and H300), the output of the fifth Hall element pair 125 (H60, H240) in arrangement C ′, and the sixth Hall The outputs of the element pair 126 (H150 and H330) are output to the MUX 225, respectively. The MUX 225 outputs the output of the first Hall element pair 121 (H0, H180) in the arrangement A ′ and the output of the second Hall element pair 122 (H90 and H270) at the time φ1 to the X-axis subtractors 226X and Y, respectively. It outputs to the axis subtraction part 226Y. At time φ2, the output of the third Hall element pair 123 (H30, H210) in the arrangement B ′ and the output of the fourth Hall element pair 124 (H120 and H300) are respectively converted into the X-axis subtractor 226X and the Y-axis subtractor. To 226Y. At time φ3, the output of the fifth Hall element pair 125 (H60, H240) in the arrangement C ′ and the output of the sixth Hall element pair 126 (H150 and H330) are respectively converted into the X-axis subtractor 226X and the Y-axis subtractor. To 226Y.

  The outputs of the X-axis and Y-axis subtraction units 226X and 226Y are input to the angle calculation unit 227. In the angle calculator 227, the angle θ of the XY coordinate system is corrected at time φ1, the angle θ30 of the XY30 coordinate system is corrected at time φ2, and the angle θ60 of the XY60 coordinate system is corrected at time φ3. Are output to the first storage register 228a, the second storage register 228b, and the third storage register 228c, respectively. The first storage register 228a, the second storage register 228b, and the third storage register 228c output the angles θ, θc, and θc ′ to the average calculation unit 229 and the failure detection unit 230, respectively. The average value calculation unit 229 calculates θave from θ, θc, and θc ′. In θave, the angle error due to magnetic saturation is reduced.

  On the other hand, θ and θc input to the failure detection unit 230 are input to the first subtraction unit 231a, and θc and θc ′ are input to the second subtraction unit 231b. The first subtraction unit 231a and the second subtraction unit 231b output θd and θd ′ to the first threshold value comparison unit 233a and the second threshold value comparison unit 233b, respectively. The first threshold value comparison unit 233a and the second threshold value comparison unit 233b compare θd_lim stored in the threshold value memory (reference signal output unit) 232 with the outputs of the first and second subtraction units 231a and 231b, respectively, If the saturation is detected, “1” is output to the logical sum unit 234, and “0” is output to the logical sum unit 234 if it is not magnetic saturation. The logical sum unit 234 outputs the logical sum of the outputs from the first and second threshold comparison units 233a and 233b as saturation information. Therefore, saturation can be detected if either θd or θd ′ is greater than θd_lim.

In the above example, θd_lim is a common reference signal for θd and θd ′, but θd_lim is the first reference signal for θd, and θd ′ is the second reference signal for θd ′. _Lim may be prepared. That is, in the above example, the first reference signal and the second reference signal are the same.
As described above, as can be understood from the description of the embodiment, in the XY coordinate system formed by the Hall element group under the magnetic convergence plate, the angular error generated by the magnetic saturation is a periodic wave of the fourth harmonic, Magnetic saturation detection is performed by generating a quadrature wave of an angular error having a different phase in another XY coordinate system formed by another Hall element group and subtracting the phase difference (angle difference). I was able to do it quickly and reliably.

In the present invention, a coordinate system that generates an angle error waveform having a different phase with respect to an angle error waveform generated by magnetic saturation in the XY coordinate system serving as a reference may be prepared. The coordinate system is not limited to two or three.
In the description of the embodiment of the present invention, for the sake of simplicity, the number of Hall elements constituting each coordinate system is four and the number of Hall elements is two for each coordinate axis component. However, the coordinate axes are equivalent. However, the number of Hall elements is not limited to this. For example, in the first embodiment, in each of the XY coordinate system and the XY45 coordinate system, each axis is set to two Hall elements. However, the number may be four.

  FIG. 17 is a diagram illustrating a modification of the first embodiment illustrated in FIG. 7, and is a diagram illustrating the arrangement of the Hall elements when the total number of Hall elements under the circumference of the magnetic flux concentrating plate is 16. In other words, when a plurality of Hall element pairs are defined on the magnetic converging plate, two Hall element pairs are sandwiched with a coordinate axis having an angle that is an integer multiple of 90 ° / N with respect to the origin of the polar coordinates. Has been placed. Here, N = 2, and a plurality of Hall elements are arranged with a pair of Hall elements sandwiching the coordinate axes of the coordinate system of 0 times and 1 time of 90 ° / N. In FIG. 17, in the counterclockwise direction below the circumference of the magnetic focusing plate, H0_A, H0_B, H45_A, H45_B, H90_A, H90_B, H135_A, H135_B, H180_A, H180_B, H225_A, H225_B, H270_A, H270_B, H315_B, H315_B, H315_A, Hall elements are lined up.

  The number of each Hall element name represents an angle from the X axis, the subscript A represents a deviation −δ (degrees) from the angle, and B represents the deviation + δ (degrees) (0 ° <δ <22.5). °). That is, H45_A has an angle of 45-δ degrees from the X axis, and H45_B has an angle of 45 + δ degrees from the X axis. Then, the X axis is on the straight line passing through the midpoint of H0_A and H0_B from the midpoint of H180_A and H180_B, the Y axis is on the straight line passing through the midpoint of H90_A and H270_B, and H225_A and H225_B When the X45 axis is formed on the straight line passing through the midpoint of H45_A and H45_B from the midpoint, and the Y45 axis is formed on the straight line passing through the midpoint of H135_A and H135_B from the midpoint of H315_A and H315_B, as in the first embodiment, XY A coordinate system and an XY45 coordinate system can be formed.

  That is, the 1A Hall element pair 21A (H0_A, H180_A) and the 1B Hall element pair 21B (H0_B, H180_B) are arranged with the coordinate axis of 0 ° therebetween. The 3A Hall element pair 23A (H45_A, H225_A) and the 3B Hall element pair 23B (H45_B, H225_B) are arranged across a 45 ° coordinate axis. The 2A Hall element pair 22A (H90_A, H270_A) and the 2B Hall element pair 22B (H90_B, H270_B) are arranged with a 90 ° coordinate axis in between. The 4A Hall element pair 24A (H135_A, H315_A) and the 4B Hall element pair 25B (H135_B, H315_B) are arranged with a 90 ° coordinate axis in between.

  That is, the difference between the output sum of H0_A and H0_B and the output sum of H180_A and H180_B becomes the X component (HVX) of the rotating magnetic field, and the difference between the output sum of H90_A and H90_B and the output sum of H270_A and H270_B is the Y component (HVY). ), The difference between the output sum of H45_A and H45_B and the output sum of H225_A and H225_B becomes the X45 component (HVX45), the difference between the output sum of H135_A and H135_B, and the difference of the output sum of H315_A and H315_B is the Y45 component (HVY45) Become. A method of calculating each axis component by using two or more Hall elements is described in Patent Document 6 described above.

In other words, a plurality of pairs of the plurality of Hall element pairs are formed by one set (four pairs) formed by 1A, 1B, 2A, and 2B and 3A, 3B, 4A, and 4B. This means that there are a plurality of pairs of four Hall element pairs corresponding to a plurality of pieces of rotation angle information.
By doing so, the components of the coordinate axes X, Y, X45, and Y45 of Embodiment 1 can be equivalently configured by four Hall elements, and the present invention can be implemented.
Similarly, each coordinate axis component of the second embodiment can be equivalently constituted by four Hall elements, and the present invention can be implemented.
In each of the embodiments described so far, the description of detecting magnetic saturation based on the difference θd between the first rotation angle θ calculated from the Hall element of the arrangement A and the second rotation angle θc calculated from the Hall element of the arrangement B is described. went. By adding an angle amplitude calculation unit to the configuration of each of the embodiments so far, magnetic saturation can be detected with higher accuracy, which will be described below.

[Embodiment 3]
FIG. 18 is a configuration diagram showing a signal processing circuit of the third embodiment of the rotation angle measuring apparatus according to the present invention. The arrangement of the magnetic flux concentrating plate and the Hall element is the same as in FIG. 7 of the first embodiment described above.
The rotation angle measuring device shown in FIG. 18 includes a first Hall element pair 21 (H0, H180) and a second Hall element pair 22 (H90, H270) in arrangement A, and a third Hall element pair in arrangement B. 23 (H45, H225), fourth Hall element pair 24 (H135, H315), MUX25, X-axis subtractor 26X, Y-axis subtractor 26Y, angle amplitude calculator (angle calculator 41 and amplitude calculator) Unit 42) 40, a first storage register 28a, a second storage register 28b, a third storage register 28c, a fourth storage register 28d, an average value calculation unit 29, and a failure detection unit 30. Has been.

That is, the rotation angle measuring apparatus according to the third embodiment includes a plurality of Hall elements H0 to H315 provided on the substrate, and a magnetic convergence plate 14 provided on the magnetic sensitive surfaces of the plurality of Hall elements H0 to H315. And a rotation angle measuring device that measures a rotation angle of a rotating magnet disposed in the vicinity of the magnetic flux converging plate 14 so as to cover the magnetic flux converging plate 14 in plan view.
A first Hall element pair 21 (H0, H180) for detecting a magnetic component in the first direction and a second Hall element pair 22 (for detecting a magnetic component in a second direction different from the first direction) H90, H270), a third Hall element pair 23 (H45, H225) for detecting a magnetic component in a third direction different from the first direction and the second direction, and the first direction to the second direction. And a fourth Hall element pair 24 (H135, H315) that detects a magnetic component in a fourth direction that is different from the third direction.

The angle amplitude calculation unit 40 includes an angle calculation unit 41 and an amplitude calculation unit 42.
The angle calculation unit 41 calculates the first rotation angle θ of the rotating magnet based on the output signal strengths of the first hall element pair 21 and the second hall element pair 22, and the third hall element pair 23 and The second rotation angle θc of the rotating magnet is calculated based on the output signal intensity of the fourth Hall element pair 24. That is, the angle calculation unit includes a plurality of pairs of Hall element pairs (first Hall element pair 21 and second Hall element pair 22, third Hall element pair 23, and fourth Hall element pair 24). A plurality of pieces of rotation angle information of the rotating magnet are calculated based on the output signal intensity. That is, the plurality of pairs include one set (one pair) constituted by the first Hall element pair 21 and the second Hall element pair 22, and the third Hall element pair 23 and the fourth Hall. One pair (one pair) composed of the element pair 24, and a pair composed of two Hall element pairs among the plurality of Hall element pairs respectively corresponds to a plurality of rotation angle information. Means there are multiple. Here, the output signal strength is the voltage of the output signal. That is, it is a Hall electromotive force signal output by the Hall element according to the input magnetic field.

The amplitude calculation unit 42 calculates the first amplitude value M representing the magnetic field strength from the rotating magnet based on the output signal strengths of the first Hall element pair 21 and the second Hall element pair 22, and the third Based on the output signal strengths of the Hall element pair 23 and the fourth Hall element pair 24, a second amplitude value Mc representing the magnetic field strength from the rotating magnet is calculated. That is, the amplitude calculation unit 42 includes a plurality of pairs (first Hall element pair 21 and second Hall element pair 22, third Hall element pair 23, and fourth Hall element respectively corresponding to a plurality of rotation angle information. A plurality of amplitude information based on the output signal of the pair 24) is calculated.
Further, the failure detection unit 30 detects a failure of the rotation angle measuring device based on the first and second rotation angles θ and θc, and further, the first and second amplitude values M and Mc, and provides failure information. Output. The average value calculator 29 calculates the average value θave from the first rotation angle θ and the second rotation angle θc.

The rotation angle measuring apparatus shown in FIG. 18 outputs the output of the first Hall element pair 21 (H0, H180) of the arrangement A, the output of the second Hall element pair 22 (H90 and H270), and the output of the arrangement B. The output of the third Hall element pair 23 (H45, H225) and the output of the fourth Hall element pair 24 (H135 and H315) are output to the MUX 25, respectively.
The MUX 25 outputs the output of the first Hall element pair 21 (H0, H180) in the arrangement A and the output of the second Hall element pair 22 (H90 and H270) at the time φ1 to the X-axis subtractor 26X and the Y-axis, respectively. It outputs to the subtraction part 26Y. X-axis subtractor 26X and Y-axis subtractor 26Y output output signals HVX and HVY to angle calculator 41 and amplitude calculator 42 of angle amplitude calculator 40, respectively.

The angle calculation unit 41 calculates the angle θ of the XY coordinate system at time φ1 and outputs it to the first storage register.
At time φ1, the amplitude calculation unit 42, for example, uses the following formula: M = sqrt (HVX ² + HVY ² )
Accordingly, the first amplitude value M representing the magnetic field strength is calculated and output to the third storage register. Note that sqrt (X) is a function for calculating the square root of X. Also, if not magnetic saturation, it is clear that the M = V _B, HVX, signal amplitude HVY, i.e., it is a signal amplitude representative of the field strength from the rotating magnet is apparent.
At time φ2, the MUX outputs the outputs of the third Hall element pair 23 (H45, H225) and the fourth Hall element pair 24 (H135 and H315) of the arrangement B to the X-axis subtracting units 26X and Y, respectively. Output to the axis subtractor 26Y. The X-axis subtractor 26X and the Y-axis subtractor 26Y output the output signals HVX45 and HVY45 to the angle calculator 41 and the amplitude calculator 42 of the angle amplitude calculator 40, respectively.

The angle calculation unit 41 calculates the angle θ45 of the XY45 coordinate system at time φ2, and outputs the angle θc corrected by 45 ° to the second storage register.
At time φ2, the amplitude calculator 42, for example, uses the following formula: Mc = sqrt (HVX45 ² + HVY45 ² )
Then, the second amplitude value Mc representing the magnetic field strength is calculated and output to the fourth storage register. Incidentally, if not the same magnetic saturation before, it is clear that the Mc = V _B, HVX45, HVY45 signal amplitude, i.e., it is a signal amplitude representative of the field strength from the rotating magnet, it is obvious.
The first and second storage registers 28a and 28b output θ and θc to the average value calculation unit 29 and the failure detection unit 30, respectively. The third and fourth storage registers 28c and 28d output M and Mc to the failure detection unit 30, respectively.
The average value calculation unit 29 calculates θave from θ and θc. In θave, the angle error due to magnetic saturation is reduced. The failure detection unit 30 detects a failure from θ, θc, M, and Mc, and outputs failure information.

FIG. 19 is a circuit configuration diagram showing a specific example of the failure detection unit shown in FIG.
19, the failure detection unit 30 includes a first subtraction unit 31a, a first comparison unit 33a, a first threshold memory (first reference signal output unit) 32a, and a second subtraction unit 31b. The second comparison unit 33b, a second threshold memory (second reference signal output unit) 32b, and a logical sum unit (failure combination determination unit) 34 are included.
The first subtraction unit 31a calculates θd from the first rotation angle θ and the second rotation angle θc, and outputs the calculated θd to the first comparison unit 33a. The first comparison unit 33a detects a failure from θd and the first threshold memory (threshold value) θd_lim, for example, “1” in the case of failure and “0” in the case of normality. The first failure determination signal is output to the logical sum unit 34.

From the first amplitude value M and the second amplitude value Mc, the second subtraction unit 31b
Md = M−Mc
Is calculated and output to the second comparison unit 33b. The second comparison unit 33b detects a failure from Md and the second threshold memory (threshold value stored in) Md_lim, for example, “1” in the case of failure and “0” in the case of normality. The second failure determination signal is output to the logical sum unit 34.
The logical sum unit 34 receives the first and second failure determination signals from the first comparison unit 33a and the second comparison unit 33b and outputs failure information. That is, the logical sum unit 34 outputs “1” when at least one of the first and second failure determination signals is a failure, and outputs “0” when both are normal.

FIG. 20 shows the amplitude value M (solid line) calculated from the output of the Hall element in the arrangement A and the output of the Hall element in the arrangement B before the magnetic saturation with respect to the magnetic convergence plate of the rotation angle measuring device shown in FIG. It shows how the calculated amplitude value Mc (dotted line), amplitude value M (one-dot chain line) and amplitude value Mc (two-dot chain line) after magnetic saturation change with respect to the rotation of the input magnetic field. FIG.
Although there is no difference between M and Mc before magnetic saturation, both M and Mc after magnetic saturation have positive or negative peaks at an angle of K × 45 ° (K is an integer from 0 to 7). It can be seen that they are oscillating and are quadruples whose phases are 180 ° different from each other. And it turns out that the lowest value of the vibration exists in the vicinity of M and Mc before magnetic saturation.
Therefore, it has been difficult to accurately determine whether or not magnetic saturation occurs depending on the rotation angle of the magnetic field by observing only one amplitude value M (or Mc). For example, even if the threshold value M_lim in FIG. 20 is set as the magnetic saturation point with respect to the amplitude M, when the input magnetic field is near 45 degrees, M is lower than M_lim, so that magnetic saturation occurs immediately. It was difficult to judge accurately.

FIG. 21 is a diagram illustrating a simulation result of θd and Md when a rotating magnetic field equal to or higher than the magnetic saturation point is applied to the magnetic convergence plate of the rotation angle measuring device illustrated in FIG. 18. The horizontal axis represents the rotation angle of the magnetic field, and the vertical axis represents θd and Md. θd is drawn with a solid line, and Md is drawn with a broken line.
Similar to the first embodiment described above, it is a fourth harmonic due to magnetic saturation, and θd is not 0 except for an angle of K × 45 degrees. The positive peak of θd is 67.5 + 90 × L degrees (L is an integer from 0 to 3). The negative peak of θd is 22.5 + 90 × L degrees.
Md is the same fourth harmonic as θd, but unlike θd, Md is not 0 and the phase is advanced by 90 degrees with respect to θd, except for an angle of 22.5 + K × 45 degrees. . The positive peak for Md is 90 × L degrees and the negative peak is 45 + 90 × L degrees. Therefore, where θd is 0, Md does not become 0.

If magnetic saturation does not occur, the strength of the magnetic field observed from the Hall element does not change in either the XY coordinate system or the XY45 coordinate system. That is, M = Mc. Therefore, Md is 0. However, when magnetic saturation occurs, M and Mc are waveforms with different phases,
Md = M−Mc ≠ 0
It is. Therefore, if an appropriate threshold value Md_lim is determined for Md, in the second comparison unit,
| Md | <Md_lim
According to the relational expression (| Md | is the absolute value of Md), if | Md | is larger than Md_lim, it can be detected that magnetic saturation occurs even with Md alone.
Since there is a relationship that Md does not become 0 when θd is 0, magnetic saturation cannot be detected when θd is 0 in the first embodiment. However, since Md is not 0 at that time, θd Magnetic saturation can be detected instead of.

Therefore, the first comparison unit 33a detects magnetic saturation (failure) from θd and θd_lim, outputs a first failure determination signal to the logical sum unit 34, and the second comparison unit 33b determines from Md and Md_lim. Magnetic saturation (failure) is detected, and a second failure determination signal is output to the logical sum unit 34. In the logical sum unit 34, the logical sum of the first and second failure determination signals is calculated. Fault information can be output at the rotation angle of the magnetic field. That is, the failure detection unit 30 detects that the rotation angle measurement device has failed based on the first failure determination signal indicating whether or not the rotation angle measurement device has failed based on the output of the angle calculation unit 41 and a plurality of pieces of amplitude information. When at least one of the second failure determination signals indicating whether or not is a failure, it is determined that the rotation angle measuring device has failed.
As described above, according to the present invention, a failure of the rotation angle measuring device is detected from the first and second rotation angles θ and θc and the first and second amplitude values M and Mc, and the failure information is output. We were able to. The detection of the failure does not depend on the angle of the input rotating magnetic field as compared with the first embodiment, and the number of Hall elements is reduced as compared with the second embodiment, and an amplitude calculation unit that can be implemented with a small-scale calculation is added It is possible to detect a failure with certainty.

FIG. 22 is a circuit configuration diagram showing another specific example of the failure detection unit in FIG.
The failure detection unit 30 in FIG. 22 includes a first subtraction unit 31a, a first comparison unit 33a, a first threshold memory 32a, a second comparison unit 33b, a second threshold memory 32b, 3 comparison units 33c, a third threshold memory (third reference signal output unit) 32c, and a logical sum unit (failure combination determination unit) 34.
The first subtraction unit 31a, the first comparison unit 33a, and the first threshold memory 32a are the same as those in FIG.

  The second comparison unit 33b detects a failure from the first amplitude value M and the second threshold memory (threshold value) M_lim. For example, when M is larger than M_lim, “1 ”(Failure) is smaller than M_lim, a second failure determination signal that is“ 0 ”(normal) is output to the logical sum unit 34. The third comparison unit 33c detects a failure from the second amplitude value Mc and the third threshold value memory (threshold value) Mc_lim. For example, when Mc is larger than Mc_lim, the third comparison unit 33c is “1” ( If the failure is smaller than Mc_lim, a third failure determination signal that is “0” (normal) is output to the logical sum unit 34. M_lim and Mc_lim may be the same value (hereinafter, the same value will be described). That is, like each comparison unit of the failure detection unit 30 in FIG. 19, each comparison unit of the failure detection unit 30 in FIG. 22 outputs “1” in the case of failure and “0” in the case of normality. is there.

As can be seen from FIG. 20 and FIG. 21, when θd is 0 and magnetic saturation cannot be detected from the difference between the first rotation angle θ and the second rotation angle θc, either M or Mc can set M_lim. It must be exceeded. For example, when the magnetic field rotation angle is 0 degree, θd is 0, but M exceeds M_lim. When the magnetic field rotation angle is 45 degrees, θd is 0, but Mc exceeds M_lim (= Mc_lim). Therefore, one of the second and third failure determination signals output from the second comparison unit 33b and the third comparison unit 33c outputs “1” or “0”.
Therefore, by calculating the logical sum of the first, second, and third failure determination signals in the OR unit 34, failure information can be output at all magnetic field rotation angles. That is, the failure detection unit 30 determines that the rotation angle measurement device has failed when at least one of the first to third failure determination signals indicates failure.
That is, according to the present invention, it is possible to accurately output failure information at all magnetic field rotation angles, which is difficult when only θd, M, or Mc is observed.

FIG. 23 is a circuit configuration diagram showing still another specific example of the failure detection unit in FIG.
The failure detection unit 30 in FIGS. 19 and 22 detects whether a failure of magnetic saturation has occurred from the first and second rotation angles θ and θc and the first and second amplitude values M and Mc. However, the failure detection unit 30 in FIG. 23 can detect whether a failure has occurred in the Hall element or magnetic saturation has occurred.
The failure detection unit 30 in FIG. 23 includes a first subtraction unit 31a, a first comparison unit 33a, a first threshold memory 32a, a second subtraction unit 31b, a second comparison unit 33b, 2 threshold memory 32b and a saturated failure determination unit (failure combination determination unit) 35.

The first subtraction unit 31a calculates θd from the first rotation angle θ and the second rotation angle θc, and outputs the calculated θd to the saturation failure determination unit 35 and the first comparison unit 33a. The first comparison unit 33a detects a failure from θd and the first threshold memory (threshold value) θd_lim, for example, “1” in the case of failure and “0” in the case of normality. The first failure determination signal is output to the saturated failure determination unit 35.
The second subtractor 31b calculates Md from the first amplitude value M and the second amplitude value Mc, and outputs the calculated Md to the saturated failure determination unit 35 and the second comparison unit 33b. The second comparison unit 33b detects a failure from Md and the second threshold memory (threshold value stored in) Md_lim, for example, “1” in the case of failure and “0” in the case of normality. The second failure signal is output to the saturated failure determination unit 35.

  The saturation failure determination unit 35 receives the first rotation angle, θd, the first failure determination signal, Md, and the second failure determination signal, and whether the Hall element has failed or magnetic saturation has occurred. In the case of a Hall element failure, failure information is output, and in the case of magnetic saturation, saturation information is output as failure information. That is, the saturation failure determination unit 35 includes one rotation angle information among a plurality of rotation angle information, a difference between two rotation angle information among a plurality of rotation angle information, and two amplitude information among a plurality of amplitude information. Based on the difference, the first failure determination signal, and the second failure determination signal, determination of magnetic saturation of the magnetic convergence plate and determination of failure of a plurality of Hall elements (a plurality of Hall element pairs) are performed. .

FIG. 24 shows an angle error Δθ of the first rotation angle θ when the magnetic focusing plate is magnetically saturated and when the output of the Hall element H0 in the XY coordinate system is short-circuited (output is 0). It is a figure showing the simulation result of (theta) d and Md.
When the magnetic saturation occurs, θd is indicated by a solid line, angle error Δθ of the first rotation angle θ is indicated by a dotted line, Md is indicated by a broken line, θd when the output of the Hall element H0 is short-circuited, and a dot-dash line and Md are indicated by a two-dot chain line. Yes. Since no failure has occurred in the third and fourth Hall element pairs in the XY45 coordinate system, the angle error Δθc of the second rotation angle θc is 0, and the angle error Δθ of the first rotation angle θ coincides with θd. I will omit it.

As can be seen from FIG. 24, when the angle difference θd is 0, Δθ is 0 even if the magnetic saturation occurs or a failure occurs, so that the calculated first rotation angle θ is correct. . For example, the amplitude difference Md when the rotation angle of the magnetic field is 0 degree is positive in the case of magnetic saturation, but is negative in the case of a failure of the Hall element. Accordingly, when the angle difference is θd = 0 and the first rotation angle θ is 0, if the amplitude difference Md is not 0 but negative, the Hall element H0 is short-circuited. If Md is not 0 but positive, it can be determined that magnetic saturation has occurred.
As shown in Table 2 below, failure of other Hall elements H45, H90, H135, H180, H225, H270, and H315 can be determined in the same procedure. In the table, θd, first failure determination signal, Md, second failure determination signal, first rotation angle θ, positive / negative of Md, and determination results are displayed as columns.

That is, the first rotation angle θ, the output θd of the first subtraction unit 31a, the output of the first comparison unit 33a, the output of the second subtraction unit 31b, and the output of the second comparison unit 33b In response, the saturation failure determination unit 35 performs the above determination to output failure information in the case of a Hall element failure and saturation information in the case of magnetic saturation as failure information.
That is, from the first and second rotation angles θ and θc and the first and second amplitude values M and Mc, the failure detection unit 30 determines whether a failure has occurred in the Hall element or magnetic saturation has occurred. I was able to detect if
Since the effect of the present invention can determine what kind of failure has occurred, it is very useful especially in a rotation angle sensor used in an application where safety requirements are strict such as for in-vehicle use.
As described above, as can be understood from the description of the embodiment, in the XY coordinate system formed by a certain Hall element group under the magnetic convergence plate, the angular error generated by the magnetic saturation and the amplitude value indicating the strength of the input magnetic field are referred to as a quadruple wave. By generating a quadruple wave of an amplitude value representing an angular error and an input magnetic field intensity that is periodic and has a phase different from this in another XY coordinate system formed by another Hall element group, From the angle and amplitude value of the XY coordinate system and the angle and amplitude value of the other coordinate system, it was possible to accurately detect magnetic saturation or to detect a failure of the Hall element.

  In the description of the third embodiment having the amplitude calculation unit 42 described above, the failure detection unit 30 detects the magnetic saturation using the first and second rotation angles θ and θc, and further the first and second amplitude values. Although it is based on M and Mc, as is clear from the above description, it is based on the first and second amplitude values M and Mc without using the first and second rotation angles θ and θc. Alone, more accurate detection of magnetic saturation is possible compared to the prior art. That is, the magnetic saturation is more accurately calculated from the second subtraction unit 31b, the second comparison unit 33b, and the second threshold memory (second reference signal output unit) 32b of the failure detection unit 30 illustrated in FIG. Detection (output of failure information) is possible. Further, the second comparison unit 33b, the second threshold memory 32b, the third comparison unit 33c, and the third threshold memory (third reference signal output unit) of the failure detection unit 30 illustrated in FIG. From 32c, more accurate detection of magnetic saturation (output of failure information) is possible. In these cases, the rotation angle may not be calculated a plurality of times. Such a case is also included in the present invention. However, based on the first and second rotation angles θ and θc and the first and second amplitude values M and Mc, failure information at all magnetic field rotation angles can be output accurately. Therefore, it is preferable.

  In the description of the third embodiment having the amplitude calculation unit 42 described above, the arrangement of the magnetic flux converging plate and the Hall element is assumed to be the same as in FIG. 7 of the first embodiment described above. That is, the XY45 coordinate system as an additional coordinate system is obtained by rotating the XY coordinates by 45 ° around G with respect to the XY coordinate system. However, the present invention also includes the amplitude calculation unit 42 as described above. It is not limited to arrangement. That is, even in the case of an additional coordinate system that is not 45 ° centered on G, when magnetic saturation occurs, the fourth harmonic of the first amplitude value M that represents the intensity of the input magnetic field calculated in the XY coordinate system, The fourth harmonic wave of the second amplitude value Mc calculated in another coordinate system has a different phase and can detect magnetic saturation more accurately, and such a case is also included in the present invention. However, in the case of the coordinate system rotated by 45 ° around G, the phase of the fourth harmonic of the amplitude value is shifted by 180 °, so that the detection sensitivity is the highest in comparison between the two, and the present invention is used. It is suitable for doing.

  In the description of each embodiment of the present invention, the MUX, the subtraction unit, the angle calculation unit, and the amplitude calculation unit after the Hall elements are shared in the signal processing circuit configurations of FIGS. 10A to 10D, FIGS. 16 and 18. In the above description, the signals from the Hall elements in each arrangement group have been acquired in a time-sharing manner. However, in order to perform high-speed processing, an X-axis subtraction unit, a Y-axis subtraction unit, an angle calculation unit, and an amplitude calculation A signal processing unit may be provided continuously for each Hall element arrangement group. Further, the average calculation unit and the failure detection unit may be configured by an external CPU or the like without being formed on the same substrate as the Hall element. Such a configuration of the signal processing circuit is also included in the technical scope of the present invention.

  All the embodiments described above are systems that conform to ISO 26262, and the angle calculation unit is an ISO 26262-compliant angle information output unit that outputs rotation angle information of a rotating magnet in accordance with ISO 26262. From another viewpoint, all of the above-described embodiments are functional safety systems, and the angle calculation unit is functionally safe, that is, the functional safety angle information is output to the functionally safe, that is, the rotational angle information of the rotating magnet. It is an output unit. Further, from another point of view, all of the above-described embodiments are rotation angle information dual system output systems, and the angle calculation unit outputs a double angle information output unit that outputs double rotation angle information of a rotating magnet. It is.

[Embodiment 4]
FIG. 25 is a configuration diagram illustrating a signal processing circuit according to the fourth embodiment of the rotation angle measurement device according to the present invention. The arrangement of the magnetic flux concentrating plate and the Hall element is the same as in FIG. 7 of the first embodiment described above.
As described above, in the configuration of the signal processing circuits of FIGS. 10A to 10D, FIG. 16 and FIG. 18, in order to perform high-speed processing, an X-axis subtracting unit, a Y-axis subtracting unit, an angle calculating unit, and an amplitude calculating unit are provided. The signal processing may be performed continuously by providing each Hall element arrangement group.
In FIG. 25, the rotation angle measuring device includes a first Hall element pair 21 (H0, H180) and a second Hall element pair 22 (H90, H270) in arrangement A, and a third Hall element pair 23 in arrangement B. (H45, H225), the fourth Hall element pair 24 (H135, H315), the first X-axis subtractor 26X1, the first Y-axis subtractor 26Y1, the first angle calculator 41a, 1 storage register 28a, second X-axis subtractor 26X2, second Y-axis subtractor 26Y2, second angle calculator 41b, second storage register 28b, and average value calculator 29 The failure detection unit 30 is configured. The failure detection unit 30 includes a subtraction unit 31, a threshold comparison unit 33, and a threshold memory 32.

The first angle calculation unit 41 a calculates the first rotation angle θ of the rotating magnet based on the output signal strengths of the first Hall element pair 21 and the second Hall element pair 22. The second angle calculator 41 b calculates the second rotation angle θc of the rotating magnet based on the output signal strengths of the third Hall element pair 23 and the fourth Hall element pair 24. That is, in the fourth embodiment, two angle calculation units calculate a plurality of pieces of rotation angle information.
Since the average value calculation unit 29 and the failure detection unit 30 are the same as those in the first embodiment described above, description thereof is omitted.
In FIG. 25, the output of the first Hall element pair 21 (H0, H180) in the arrangement A is input to the first X-axis subtracting unit 26X1. The output of the second Hall element pair 22 (H90 and H270) is input to the first Y-axis subtractor 26Y1. The first X-axis subtractor 26X1 and the first Y-axis subtractor 26Y1 output output signals HVX and HVY to the first angle calculator 41a, respectively.

The first angle calculation unit 41a calculates the angle θ of the XY coordinate system from HVX and HVY, and outputs it to the first storage register 28a.
The output of the third Hall element pair 23 (H45, H225) in the arrangement B is input to the second X-axis subtracting unit 26X2. The output of the fourth Hall element pair 24 (H135 and H315) is input to the second Y-axis subtractor 26Y2. The second X-axis subtractor 26X2 and the second Y-axis subtractor 26Y2 output the output signals HVX45 and HVY45 to the second angle calculator 41b, respectively.
The second angle calculation unit 41b calculates the angle θ45 of the XY45 coordinate system from the HVX45 and the HVY45, and outputs the angle θc corrected by 45 ° to the second storage register 28b. The first and second storage registers 28a and 28b output θ and θc to the average value calculation unit 29 and the failure detection unit 30, respectively.

The operations of the average value calculation unit 29 and the failure detection unit 30 are the same as those described in the first embodiment.
Since the rotation angle measuring device is configured in this way, the first rotation angle and the second rotation angle can be calculated simultaneously, so that high-speed signal processing is possible, highly accurate angle calculation, and magnetic saturation detection. Can be performed at high speed.
In addition, since the first rotation angle and the second rotation angle are calculated by the separate angle calculation units as described above, when a failure occurs between the Hall element and the angle calculation unit, the failure detection unit In the same manner as in the first embodiment, the difference θd between the first rotation angle and the second rotation angle is set to an appropriate threshold value θd_lim.
| Θd | <θd_lim
It is possible to detect a failure with the relational expression.
That is, according to the present invention, not only magnetic saturation but also a failure from the Hall element to the angle calculation unit can be detected.

[Embodiment 5]
FIG. 26 is a block diagram showing a signal processing circuit of the fifth embodiment of the rotation angle measuring apparatus according to the present invention. The fifth embodiment is a configuration diagram illustrating a configuration of a continuous signal processing circuit when the angle amplitude calculation unit of the third embodiment described above is separately provided. The arrangement of the magnetic flux concentrating plate and the Hall element is the same as in FIG. 7 of the first embodiment described above.
In FIG. 26, the rotation angle measuring device includes a first Hall element pair 21 (H0, H180) and a second Hall element pair 22 (H90, H270) in arrangement A, and a third Hall element pair 23 in arrangement B. (H45, H225), a fourth Hall element pair 24 (H135, H315), a first X-axis subtractor 26X1, a first Y-axis subtractor 26Y1, a first angular amplitude calculator 40a, The first storage register 28a, the third storage register 28c, the second X-axis subtraction unit 26X2, the second Y-axis subtraction unit 26Y2, the second angular amplitude calculation unit 40b, and the second storage The register 28b, the fourth storage register 28d, an average value calculation unit 29, and a failure detection unit 30 are included.

The first angle amplitude calculation unit 40a includes a first angle calculation unit 41a and a first amplitude calculation unit 42a. The second angle amplitude calculation unit 40b includes a second angle calculation unit 41b and a second amplitude calculation unit 42b.
The first angle calculation unit 41 a calculates the first rotation angle θ of the rotating magnet based on the output signal strengths of the first Hall element pair 21 and the second Hall element pair 22. The second angle calculator 41 b calculates the second rotation angle θc of the rotating magnet based on the output signal strengths of the third Hall element pair 23 and the fourth Hall element pair 24.

The first amplitude calculator 42 a calculates a first amplitude value M representing the magnetic field strength from the rotating magnet based on the output signal strengths of the first Hall element pair 21 and the second Hall element pair 22. The second amplitude calculation unit 42 b calculates a second amplitude value Mc representing the magnetic field strength from the rotating magnet based on the output signal strengths of the third Hall element pair 23 and the fourth Hall element pair 24. The operation of the average value calculation unit 29 is the same as that described in the first embodiment.
The failure detection unit 30 is configured by any of FIG. 19, FIG. 22, or FIG. 23 described in the third embodiment.

In FIG. 26, the output of the first Hall element pair 21 (H0, H180) in the arrangement A is input to the first X-axis subtracting unit 26X1. The output of the second Hall element pair 22 (H90 and H270) is input to the first Y-axis subtractor 26Y1. The first X-axis subtractor 26X1 and the first Y-axis subtractor 26Y1 respectively output the output signals HVX and HVY to the first angle calculator 41a and the first amplitude calculator 42a of the first angle amplitude calculator 40a. Output to.
The output of the third Hall element pair 23 (H45, H225) in the arrangement B is input to the second X-axis subtracting unit 26X2. The output of the fourth Hall element pair 24 (H135 and H315) is input to the second Y-axis subtractor 26Y2. The second X-axis subtractor 26X2 and the second Y-axis subtractor 26Y2 respectively output the output signals HVX45 and HVY45 to the second angle calculator 41b and the second amplitude calculator 42b of the second angle amplitude calculator 40b. Output to.

The first angle calculation unit 41a calculates the angle θ of the XY coordinate system from HVX and HVY, and outputs it to the first storage register 28a. The first amplitude calculator 42a calculates the amplitude value M from HVX and HVY and outputs it to the third storage register 28c. The second angle calculation unit 41b calculates the angle θ of the XY45 coordinate system from the HVX45 and the HVY45, and outputs it to the second storage register 28b. The second amplitude calculation unit 42b calculates the amplitude value Mc from the HVX 45 and the HVY 45, and outputs it to the fourth storage register 28d.
Since the average value calculation unit 29 and the failure detection unit 30 are the same as those of the third embodiment described above, description of the operation is omitted.
Since the rotation angle measuring device is configured in this way, the first rotation angle, the second rotation angle, the first amplitude value, and the second amplitude value can be calculated simultaneously, so that high-speed signal processing is possible. High-precision angle calculation and fault detection can be performed at high speed.

  In addition, the first rotation angle and the second rotation angle are calculated by separate angle calculation units in this way, and the first amplitude value and the second amplitude value are calculated by separate amplitude calculation units. Therefore, if a failure occurs between the Hall element and the angle amplitude calculation unit, it can be detected by the failure detection unit and the failure of the Hall element can be detected, so that the failure occurs in the Hall element of one coordinate system. However, the rotation angle measurement can be continued by using the Hall element of the other coordinate system. For example, when a failure occurs in the Hall element in arrangement A, the first rotation angle becomes unreliable, but no failure occurs in the hall element in arrangement B, so the second rotation angle is measured and continuously output. Can do. Such an effect of the present invention is very useful in a rotation angle sensor used in an application requiring strict safety such as an in-vehicle application. That is, this example is a functional safety system and a system that complies with ISO26262.

In each embodiment of the present invention, the difference between the first rotation angle and the second rotation angle, or the difference between the first amplitude value and the second amplitude value is calculated by the subtraction unit, and the threshold value is calculated by the comparison unit. However, any operation having a result similar to this is included in the present invention.
In the description of the third and fifth embodiments, the angle amplitude calculation unit 40 is divided into an angle calculation unit 41 and an amplitude calculation unit 42 to calculate the angle and the amplitude, respectively. By using (CoordinateRate Digital Computer), the angle and amplitude can be calculated simultaneously as one angle amplitude calculator. A configuration using such a calculation method is also included in the scope of the present invention.
That is, the present invention is not limited to the embodiments described so far, and design changes within a range not departing from the gist of the present invention are included in the present invention. That is, it goes without saying that various modifications and corrections that can be made by those skilled in the art are included.

1 Rotating magnet 2 Integrated circuit (silicon substrate)
3 Hall elements 4, 14 Magnetic converging plate 11X X-axis subtraction unit 11Y Y-axis subtraction unit 12 Calculation unit 21 (H0, H180) First Hall element pair 22 (H90, H270) Second Hall element pair 23 (H45, H225) Third Hall element pair 24 (H135, H315) Fourth Hall element pair 25,225 MUX (multiplexer)
26X, 226X X-axis subtractor 26X1 First X-axis subtractor 26X2 Second X-axis subtractor 26Y, 226Y Y-axis subtractor 26Y1 First Y-axis subtractor 26Y2 Second Y-axis subtractor 27, 227 Angle Calculation unit 28a, 228a First storage register 28b, 228b Second storage register 28c, 228c Third storage register 28d Fourth storage register 29, 229 Average value calculation unit 30, 230 Failure detection unit 31 Subtraction unit (difference Calculation part)
31a, 231a First subtraction unit 31b, 231b Second subtraction unit 32, 232 Threshold memory (reference signal output unit)
32a First threshold memory (first reference signal output unit)
32b Second threshold memory (second reference signal output unit)
32c Third threshold memory (third reference signal output unit)
33 Threshold comparison units 33a and 233a First threshold comparison units 33b and 233b Second threshold comparison unit 33c Third threshold comparison unit 34 OR unit (failure combination determination unit)
35 Saturation failure determination unit (failure combination determination unit)
40 angle amplitude calculation unit 40a first angle amplitude calculation unit 40b second angle amplitude calculation unit 41 angle calculation unit 41a first angle calculation unit 41b second angle calculation unit 42 amplitude calculation unit 42a first amplitude calculation unit 42b Second amplitude calculation unit 121 (H0, H180) First Hall element pair 122 (H90 and H270) Second Hall element pair 123 (H30, H210) Third Hall element pair 124 (H120 and H300) 4 Hall element pair 125 (H60, H240) 5th Hall element pair 126 (H150 and H330) 6th Hall element pair

Claims (16)

A rotation angle measuring device including a plurality of Hall element pairs,
A magnetic converging plate provided on the magnetosensitive surface of the plurality of Hall element pairs;
A rotating magnet disposed close to the magnetic focusing plate so as to cover the magnetic focusing plate in plan view;
Based on the previous SL plurality of output signals of the plurality of pairs of Hall element pair, and one or more angle calculation section that calculates a plurality of rotation angle information of the rotating magnet,
An amplitude calculation unit that calculates a plurality of amplitude information based on the plurality of pairs of output signals respectively corresponding to the plurality of rotation angle information;
Based on the plurality of rotation angle information and a difference between two pieces of amplitude information among the plurality of amplitude information and a comparison result between the first reference signal output by the first reference signal output unit, the rotation angle A failure detection unit for detecting a failure of the measuring device;
A rotation angle measuring device. A rotation angle measuring device including a plurality of Hall element pairs,
A magnetic converging plate provided on the magnetosensitive surface of the plurality of Hall element pairs;
A rotating magnet disposed close to the magnetic focusing plate so as to cover the magnetic focusing plate in plan view;
Based on the previous SL plurality of output signals of the plurality of pairs of Hall element pair, and one or more angle calculation section that calculates a plurality of rotation angle information of the rotating magnet,
An amplitude calculation unit that calculates a plurality of amplitude information based on the plurality of pairs of output signals respectively corresponding to the plurality of rotation angle information;
Of the plurality of rotation information, the comparison result between the first amplitude information of the plurality of amplitude information and the first reference signal output by the first reference signal output unit, and the plurality of amplitude information Failure detection for detecting a failure of the rotation angle measuring device based on a comparison result between the second amplitude information different from the first amplitude information and the second reference signal output from the second reference signal output unit And
A rotation angle measuring device. A rotation angle measuring device including a plurality of Hall element pairs,
A magnetic converging plate provided on the magnetosensitive surface of the plurality of Hall element pairs;
A rotating magnet disposed close to the magnetic focusing plate so as to cover the magnetic focusing plate in plan view;
An amplitude calculation unit that calculates a plurality of amplitude information representing the magnetic field intensity from the rotating magnet based on the output signals of the plurality of pairs of the plurality of Hall element pairs;
A failure detection unit that compares a difference between two pieces of amplitude information among the plurality of amplitude information and a first reference signal output by a first reference signal output unit, and detects a failure of the rotation angle measurement device;
A rotation angle measuring device. A rotation angle measuring device including a plurality of Hall element pairs,
A magnetic converging plate provided on the magnetosensitive surface of the plurality of Hall element pairs;
A rotating magnet disposed close to the magnetic focusing plate so as to cover the magnetic focusing plate in plan view;
An amplitude calculation unit that calculates a plurality of amplitude information representing the magnetic field intensity from the rotating magnet based on the output signals of the plurality of pairs of the plurality of Hall element pairs;
Of the plurality of amplitude information, the first amplitude information is compared with the first reference signal output from the first reference signal output unit, and the second amplitude different from the first amplitude information among the plurality of amplitude information. A failure detection unit that compares the amplitude information of the second reference signal output by the second reference signal output unit and detects a failure of the rotation angle measuring device;
A rotation angle measuring device. The failure detection unit further detects a failure of the rotation angle measurement device based on the plurality of rotation angle information and a third reference signal output by a third reference signal output unit. Rotation angle measuring device. The failure detection unit is
The rotation angle measurement device according to claim 5, wherein a failure of the rotation angle measurement device is detected based on two differences among the plurality of rotation angle information and the third reference signal.   The rotation angle measuring device according to claim 6, further comprising a difference calculating unit that calculates the difference. The failure detection unit is
The rotation angle measuring device according to any one of claims 1 to 7, wherein magnetic saturation of the magnetic converging plate is detected. The failure detection unit is
Based on the plurality of rotation angle information, a first failure determination signal indicating whether or not the rotation angle measurement device is in failure is output, and on the basis of the plurality of amplitude information, the rotation angle measurement device has failed. When a second failure determination signal indicating whether or not there is present and at least one of the first and second failure determination signals indicates failure, it is determined that the rotation angle measuring device is failed The rotation angle measuring device according to claim 1. The failure detection unit is
Based on the plurality of rotation angle information, a first failure determination signal indicating whether or not the rotation angle measurement device is in failure is output, and on the basis of the plurality of amplitude information, the rotation angle measurement device has failed. A second failure determination signal indicating whether or not there is, a rotation angle information of one of the plurality of rotation angle information, a difference between two rotation angle information of the plurality of rotation angle information, and the plurality of the plurality of rotation angle information Based on the difference between two pieces of amplitude information among the amplitude information, the first failure determination signal, and the second failure determination signal, determination of magnetic saturation of the magnetic convergence plate, and the plurality of Hall element pairs The rotation angle measuring device according to claim 1, further comprising a determination unit configured to determine whether or not the failure has occurred. The failure detection unit is
Based on the output of the angle calculation unit, a first failure determination signal indicating whether or not the rotation angle measurement device is out of order is output. Based on the first amplitude information, the rotation angle measurement device is out of order. A second failure determination signal indicating whether the rotation angle measuring device is in failure based on the second amplitude information, and outputting a third failure determination signal indicating whether the rotation angle measurement device is in failure, The rotation angle measurement device according to claim 2, wherein when at least one of the first to third failure determination signals indicates a failure, the rotation angle measurement device determines that the rotation angle measurement device is in failure. The plurality of pairs is at least three pairs;
The failure detection unit is
Two or more differences between two rotation angle information among the plurality of rotation angle information are calculated, and a failure of the rotation angle measuring device is detected based on the two or more differences and the third reference signal. The rotation angle measuring device according to any one of claims 5 to 7 . The failure detection unit is
The two or more differences and the third reference signal are respectively compared to output a signal indicating whether or not the rotation angle measuring device is malfunctioning, and at least one of these signals is malfunctioning. The rotation angle measurement device according to claim 12, wherein the rotation angle measurement device determines that the rotation angle device is out of order. The failure detection unit is
Based on the first amplitude information, a first failure determination signal indicating whether or not the rotation angle measuring device is out of order is output, and based on the second amplitude information, the rotation angle measuring device is out of order. A second failure determination signal indicating whether or not the rotation angle measuring device is in failure when at least one of the first to second failure determination signals indicates failure. The rotation angle measuring device according to claim 4 which judges. The plurality of Hall element pairs are:
15. When polar coordinates are defined on the magnetic converging plate, the polar coordinates are arranged so as to be shifted by 45 degrees below the circumference centered on the origin of the polar coordinates, respectively. Rotation angle measuring device. The plurality of Hall element pairs are:
When polar coordinates are defined on the magnetic converging plate, two Hall element pairs sandwiching a coordinate axis of an angle that is an integer multiple of 90 ° / N (N is an integer of 2 or more) with respect to the origin of the polar coordinates. The rotation angle measuring device according to any one of claims 1 to 15, wherein:

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